• ↑ Ppeak, normal Pplat → resistance problem (secretions, bronchospasm, kinked ETT)
• ↑ Both Ppeak and Pplat → compliance problem (ARDS, pneumothorax)
• PTA > 10 cmH₂O → elevated resistance — investigate
• PTA > 20 cmH₂O → severe obstruction — urgent
• Turbulent flow → raises Ppeak further; reduce inspiratory flow

This simulator uses Volume-Controlled Ventilation (VCV) with a constant (square wave) inspiratory flow pattern.

• Pressure–Time scalar: In VCV the ventilator delivers a fixed tidal volume regardless of lung mechanics. Ppeak rises with airway resistance or reduced compliance. Pplat reflects lung compliance only. The gap between them — PTA — is a pure measure of airway resistance.
• Flow–Time scalar: Inspiration shows a flat rectangular plateau — the hallmark of VCV constant-flow delivery. During the end-inspiratory pause (EIP), flow drops to zero and pressure equilibrates to Pplat. Expiration is entirely passive — driven by lung elastic recoil. The rate of expiratory flow decay reflects airway resistance: high resistance causes a prolonged, scooped expiratory limb.
• Turbulent flow causes the expiratory limb to become irregular and resistance rises nonlinearly with flow rate. If expiratory flow does not return to zero before the next breath, auto-PEEP develops.

PTA = Raw × Flow (laminar flow).
With turbulent flow, resistance increases further — Ppeak rises more than expected.
Reducing inspiratory flow reduces Ppeak without affecting Pplat.